Ahlawat Dharamvir Singh, Arora Sandeep
Department of Physics, Chaudhary Devi Lal University, Sirsa-125055 (Hry.), India.
J Mol Model. 2024 Apr 10;30(5):128. doi: 10.1007/s00894-024-05927-y.
Two-dimensional (2D) nanoheterostructures of materials, integrating various phase or materials into a single nanosheet have stimulated large-scale research interest for designing novel two dimensional devices. In contemporary analysis present work, we examined the structural and electronic properties of the isolated 2D BN and GaN monolayers. We have investigated the structural stability and optoelectronic and photocatalytic response of the g-GaN/BN nanoheterostructure along with its response to strain. Nanoheterostructure g-GaN/BN is predicted to be a direct bandgap semiconductor with wide gap of 4.45 eV, whose value can be effectively modulated by applied strain ( , ranging from 4.55 ( = - 4%) to 3.58 eV ( = 8%). We also discovered that the tensile strain of 8% can substantially tune the direct bandgap of nanoheterostructure to indirect band gap nature. Even more important, the biaxial tensile strain engineering accentuates an enhancement of optical absorption in the UV region, broadening the light harvesting of the g-GaN/BN nanoheterostructure with the shifting of first absorption peak from 4.64 ( = - 4%) to 3.71 eV ( = 8%). Furthermore, strain-tuned band edge potentials arrangement perfectly fits the water reduction and oxidation redox potentials. Our findings portend that the g-GaN/BN nanoheterostructure has application in prospective nanoscale optoelectronic devices and photocatalytic hydrogen evolution system.
First principles calculations in this study are performed using density functional theory. Generalized gradient approximation within PBEsol functional employed to address the electron-electron exchange-correlation effects. For avoiding periodic interactions between the layers, we have inserted a vacuum region of thickness 10 Å in the z-direction. For ensuring the convergence accuracy of the computed results, convergence criteria of the iteration process is set to be 0.0001 eV. Local modified Becke-Johnson, a semi local functional, is applied for calculating electronic and optical properties for more accuracy of results. As in layered 2D nanoheterostructure, a factual depiction of the van der Waals interactions cannot be provided by conventional DFT techniques. Accordingly, in order to incorporate these interactions, we had employed the dispersion correction method of Grimme's.
将各种相或材料整合到单个纳米片中的二维（2D）材料纳米异质结构激发了人们对设计新型二维器件的大规模研究兴趣。在当代分析工作中，我们研究了孤立的二维氮化硼（BN）和氮化镓（GaN）单层的结构和电子特性。我们研究了g-GaN/BN纳米异质结构的结构稳定性、光电和光催化响应及其对应变的响应。预测纳米异质结构g-GaN/BN是一种直接带隙半导体，带隙为4.45电子伏特，其值可通过施加应变有效调制（范围从4.55电子伏特（应变=-4%）到3.58电子伏特（应变=8%））。我们还发现8%的拉伸应变可将纳米异质结构的直接带隙显著调制成间接带隙性质。更重要的是，双轴拉伸应变工程增强了紫外区域的光吸收，随着第一个吸收峰从4.64电子伏特（应变=-4%）移动到3.71电子伏特（应变=8%），拓宽了g-GaN/BN纳米异质结构的光捕获范围。此外，应变调谐的带边电位排列完美地符合水还原和氧化的氧化还原电位。我们的研究结果预示着g-GaN/BN纳米异质结构在未来的纳米级光电器件和光催化析氢系统中有应用前景。
本研究中的第一性原理计算使用密度泛函理论进行。采用PBEsol泛函中的广义梯度近似来处理电子-电子交换关联效应。为避免层间的周期性相互作用，我们在z方向插入了厚度为10埃的真空区域。为确保计算结果的收敛精度，将迭代过程的收敛标准设置为0.0001电子伏特。应用局部修正的Becke-Johnson（一种半局域泛函）来计算电子和光学性质，以获得更准确的结果。由于在层状二维纳米异质结构中，传统的密度泛函理论技术无法真实描述范德华相互作用。因此，为了纳入这些相互作用，我们采用了Grimme的色散校正方法。
